Process of reducing lead ores.



No. 778,901, PATENTED JAN. 3, 1905.

v P. G. SALOM. PROCESS OF REDUCING LEAD ORES.

APPLICATION FILED APR. 1'7, 1903.

2 SHEETS-SHEET 1,

WITNESSES; HNVENTOR:

P. G. SALOM.

PROCESS OF REDUCING LEAD ORES.

APPLICATION FILED APB.17, 190a.

PATENTED JAN. a, 1905 2 SHEETS-SHEET 2.

llniran stares Patented January '8, 1905 ldarnwr PHOCESS OF REDUOllNG LEAD QRES SEECIFIOAT I LON forming part of Letters Patent N o."7'78,901, dated January 3, 1905,,

Application filed April 17, 1903. Serial No. 153,047.

To all Hill/0772, it may concern:

Be it known that I, PEDRO G. SALOM, a citizen of the United States, residing at N 0. i702 Chester avenue, in the city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a certain new and useful Improved Process for the Reduction ofLead ()res,of which the following is a specification, reference being had to the accompanying drawings. I

My process is applicable to the reduction of a variety of lead ores. including also argontiferous lead ores; but I will describe it as applied to the reduction of the sulfid of lead commonly known as galena. By my process 1 place the lead ore in contact Witha cathode and in the presence of an electrolyte,such as dilute sulfuric acid, and as the reduction which occurs upon the passage of the electric current. proceeds I continuously remove the resulting spongy lead from the' cathode, replacing it by a continuous supply of the ore.

Although my process is independent of any particular form of apparatus, I have illustrated in the drawings and will first describe an apparatus which 1 have found aconvenient one to employ in the practice of my process.

in the accompanying drawings, Figure l is a vertical central section of this apparatus, and Fig. 2 is a plan View of the same.

The apparatus consists of a rotating circular table A; supported by a fixed central post a.

B is an annular electrolytic cell supported upon the rotating table and concentric therewith. it has inner and outer peripheral walls 7; 7/. This cell is preferably composed of antimonial lead. It is constituted a cathode by electrical connections through the ventral post, which is insulated from the lloor on which it rests. The post (1, around which this table swings, carries above the table a spider-frame D, insulated from the post, consisting of a central disk (Z and radial arms 4'11. This spider-frame supports within the i electrolytic cell B an anode in the form of an annulus, which is incomplete to the extent of one of the spaces between the armsof the spi; der-frame. 'lhls anode is made up of a series of segmental anode-plates H, each plate a space between the arms of the spibridging their der-frame and all being supported by contact with the arms of the frame. The anode-plates are also preferably made of antimonial lead; Each anode-plate has its under surface slightly dished upward and has a central aperture h, leading to a short pipe,

from which a small rubber tube h leads to a.

chamber K, mounted on theupper endof the central post. By means of these tubes h the gaseous products of electrolysis throughout the entire electrolytic cell arelead to the chamber K, from whence they are removed by a pipe The entire series of anodeplates is constituted a'si-ngle anode by means of electrical connections through the spiderframe by way of a central insulated spindle in.

Thus far the parts which have been described constitute an annular electrolytic cell of which the bottom forms a cathode-plate. Continuous rotation is imparted to this annular cathode by means of a gear thereon, which meshes with a pinion f, fastened upon a shaft, which also carries the ratchet-wheel G, to which motion is imparted by a pawling-lever g, which in turn is slowly oscillatedby means of a link connection 9, running to 'an oscillating bar I, by which, if desired, a whole series of apparatus similar to the one now being described may be kept in motion.

I will now describe those'parts of the apparatus which have for their function to continuously spread upon the cathodeplate' at the bottom of the cell thelead ore and also to continuously remove therefrom the spongy lead which is formed on the cathode by the electrolytic action.

A supply-box P in the form of a narrow segment is supported from two short bridge-pieces which bridge the aperture between. the arms of the spiderframe,from which,as before explained, the anode-plates are lacking, all connections between the box and the spider-frame being insulated. The side wall of the box P, away from which rotation o the cathode occurs, does not reach quite to the bottom of the cell, thus leaving a feeding-slot p beneath it,

which is controlled by a sliding the aperture of plate adjustable vertically by set-screws q g.

F, formed Outside of the side Wall of the box P, toward which rotation of the cathode occurs, is mounted a vertically-sliding scraper-plate S, the position of which may be adjusted by setscrews 8 s.

The peculiarity of my process is that the supply of ore to the cathode is continuous and likewise the removal of the resulting spongy lea from the cathode, both taking place at a rate corresponding to the'time which is required to completely reduce the lead in accordance with the conditions under which the process is practiced. To accomplish this, I feed continuously to the box P a supply of properly-concentrated finely-ground galena of a grade averaging from seventy to eighty per cent. of metallic lead. The electrolytic cell is filled with an electrolyte-say dilute sulfuric acid (about ten-per-cent. solution)-enough esses where the electrodes being always present to cover the ore and the anode. The feed of the ore is at about the rate of ten pounds per hour for a current density of fifteen hundred amperes, distributed so as to provide about sixty amperes per square foot of active cathode-surface. The width of the feeding-slot is so adjusted that the total amount of ore resting on the cathode any one time is about fifteen pounds. For this purpose the slot 9 at the bottom of the box is so adjusted that as the cathode revolves in the direction of the arrow in Fig.2 a fine layer say from one-tenth to one-thirtieth of an inch thick-of the powdered ore is continuously spread over the bottom of the cell. The rate of rotation is about one turn in an hour and a half. The current passing between the electrodes reduces thelead sulfid to metallic lead, which appears as a spongy mass varying in consistency according to the fineness of the ore. It is very'porous and spongy if the ore be ground fine and more or less plastic if the ore be ground coarse. As rotation continues the spongy lead thus formed at the bottom of the cell meets as rapidly as the reduction proc ass is completed the advancing edge of the scraper-plate S and is by it scraped from the cathode. As this mass accumulates against thescraper it occupies the space in front of it and is from time to time removed from this space without interrupting'the process. By thus spreading the ore very thinly and evenly over the cathode there results a very complete reduction. This makes possible the use of larger current densities-say sixty amperes per square foot of cathode-Surface thereby hastening the reduction process. There is no loss of time and energy such as occurs in procmust from time to time be removed in order to get at the product of the electrolysis. Neither do the workmen experience any of the disagreeable or have described a .lead sulfid as the ore to be treated my invention is not limited either to this apparatus or this ore.

My process consists, broadly, current between two electrodes in the presence of -a suitable electrolyte and in continuously spreading a thin layer of the lead ore which is to be reduced upon the negative electrode and as continuously scraping off the spongy lead which forms upon this electrode as a re- .sult-of the electrolysis as rapidly as reduction is completed. By so doing the ore becomes practically itself the negative electrode or pole and the current in passing through the samedecomposes it (formingsulfureted hydrogen 1 at the pole, if the ore be lead sulfid) and leaving the lead in a spongy metallic condition. So far as I am aware, this continuous spreading of ore upon of efiecting its removal of the is reduced has not heretofore I therefore claim- 1. The process of reducing lea-d ore which i consists in continuouslyspreading the ore in a finely-ground condition upon the surface of a suitable cathode, in the presence of asuitable electrolyte and a suitable anode; maintaining reduction and as continuous been practiced.

in passing a an electrode for the purpose reduced productas soon as it the ore upon the cathode until complete I'6 duction has occurred; and then continuously removing the resultant mass of spongy'lead from the cathode-plate at a rate COIIGSPODd',

of a cathode of anti nonial lead, in. the presence of an electrolyte of dilute sulfuric acid and a suitable anode;

occurred; and then continuously removing the resultant mass of spongy lead from the cathode-plate at a rate corresponding to the rate at which the ore is as described.

to this specification,-this 15th day of April, 1903, in the. presence of two subscribing witnesses.

JAMES H. BELL, M. K. 'TRUMBORE.

maintaining the ore upon the cathode until complete reduction has spread, substantially- In testimony whereof I have signed my name KSO lead sulfid which consists in continuously spreading the sulfid' in a finely-ground condition upon the surface IIO 

